/*
 * Copyright (c) 2004-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Gou Pengfei
 *
 * Date:    Mar. 2011
 */

#ifndef __CPU_EDGE_IBTB_TONB_HH__
#define __CPU_EDGE_IBTB_TONB_HH__

#include <vector>

#include "base/misc.hh"
#include "base/types.hh"
#include "config/the_isa.hh"
#include "arch/isa_traits.hh"

/**
 * Indirect btb used by Type-Only Next-Block predictors
 * */
class IBTB
{
  private:

    enum IndexType
    {
        Unknown,
        GlobalHistory,
        PathHistory,
        ConPathHistory,
        HybridHistory
    };

    struct IBTBEntry
    {
       IBTBEntry() : 
         target(0x0),
         hysteresis(false),
         valid(false)
      {}

       Addr target;
       bool hysteresis;
       bool valid;
    };

  public:

    IBTB(unsigned numEntries, unsigned blockShiftAmt, std::string index_type);

    void reset();

    Addr lookup(const Addr &PC, uint64_t hist, uint64_t path_hist);

    void update(const Addr &PC, uint64_t hist, uint64_t path_hist,
            Addr correct_target);

  private:    

    uint64_t calcIndex(const Addr &PC, uint64_t hist, uint64_t path_hist);

    std::vector<IBTBEntry> ibtb;

    uint64_t numEntries;

    uint64_t idxLength;

    uint64_t idxMask;

    uint64_t blockShiftAmt;     

    IndexType indexType;
};

#endif // __CPU_EDGE_IBTB_TONB_HH__

